The present invention relates generally to headlamp adjusters which are used to adjust the position of a reflector of an automobile headlamp assembly, and relates more specifically to a headlamp adjuster which includes an expandable member, such as a bellows, for accommodating an end of an adjuster member when the adjuster member is retracted.
Modern day headlamps for vehicles are engineered and designed to be aerodynamically efficient. In this regard, the headlamps are designed as sealed assemblies wherein the portion of the headlamp approximate the outer surface of the automobile is relatively stationary, and is aerodynamic.
A typical modern day headlamp assembly 12 is illustrated in a plan view seen as FIG. 1, and normally includes: a fixed housing 20, to which an outer headlamp lens 22 is affixed; a movable reflector 24, which is mounted within the fixed housing 20; and a stationary headlamp bulb (not shown), which is positioned within the movable reflector 24. Typically, the movable reflector 24 is mounted to the housing 20 by a universal or ball-type pivot 26 which is stationary, or fixed, on the housing 20.
A first pivot point 28 is disposed generally vertical of the fixed pivot 26, and a second pivot point 30 is disposed generally horizontal of the fixed pivot 26. As such, the movable reflector 24 may be pivoted about the fixed pivot 26 in the vertical and horizontal planes to aim the headlamp beam. Adjustment mechanisms, or headlamp adjusters, 40 and 42 are typically provided at the first and second pivot points, 28 and 30, normally termed the vertical pivot and the horizontal pivot, and the headlamp adjusters 40 and 42 can be operated to effect movement of the reflector 24 in the vertical and horizontal planes.
The headlamp adjusters 40 and 42 are typically mounted to the housing 20 of the headlamp assembly 12 and have adjuster output shafts 44, 46 operatively connected to the movable reflector 24 by ball and socket type pivots, or the like, such that linear movement of the adjuster output shafts 44, 46 produces pivoting of the movable reflector in the vertical and horizontal planes. Specifically, each headlamp adjuster 40, 42 typically includes drive structure 48, 50 for receiving a tool, and typically the drive structure 48, 50 is precision geared to the adjuster output shaft 44, 46. The gearing provides that using the tool to rotate the drive structure 48, 50 causes linear translation of the adjuster output shaft 44, 46 and therefore adjustment of the position of the headlamp reflector 24.
Before an automobile is released to the consumer, the movable reflectors of the headlamp assemblies are adjusted to a desired position so that the headlamp beams are properly aimed in both the vertical and horizontal directions. To this end, headlamp adjusters are normally operated at the automobile assembly plant. Thereafter, if a movable reflector moves from its desired position, due, for example, to vibration, jarring, or the vehicle being in an accident, a mechanic can operate the headlamp adjusters in order to properly re-align the reflectors.
Typically, headlamp adjusters are structured such that over-travel of the adjuster shafts (i.e. 44 in FIG. 1) is not prevented. Over-travel of the adjuster shaft can cause breakage of the headlamp adjuster housing and/or the reflector to which the adjuster shaft is connected. Specifically, over-extension of the adjuster screw from the housing can damage the reflector, and over-retraction of the adjuster screw into the housing can cause the end of the adjuster screw to contact an interior wall of the housing and result in damage to the housing, such as cracking. It should be noted that these headlamp assemblies are sealed against the environment, especially the entry of moisture, which can reduce the effectiveness of the lamp and also result in rust and deterioration over time. Thus, a crack in the housing can permit moisture, dirt, etc. to enter the housing which is undesirable.
As shown in FIG. 2, one way to accommodate the retraction of the adjuster output shaft 60 is to provide that the housing 62 has a receptacle or tower 64 which receives the end 66 of the adjuster output shaft 60 as the adjuster output shaft 60 retracts (represented by arrow 68 in FIG. 3). Being generally non-expandable, the tower 64 must be long enough to accommodate full retraction of the adjuster output shaft 60 (with full retraction being defined by the specific design of the headlamp adjuster). Otherwise, full retraction of the adjuster output shaft 60 may cause the end 66 of the adjuster output shaft 60 to bear against an internal wall 70 of the tower 64, thereby stressing and possibly fracturing a weld joint 72 between the housing 62 and tower 64. Another concern is that the tower material may become brittle and excessive stress may cause cracks to develop in the tower material.
Because the tower must be long enough to accommodate full retraction of the adjuster output shaft, the headlamp adjuster is not provided as being as small as it possibly could be provided. Furthermore, some headlamp adjuster applications require that the adjuster output shaft be able to retract more than others. Therefore, it has been necessary for the manufacture to employ headlamp adjusters with different length towers, depending on the specific application. As an example, FIGS. 3a and 3b illustrate headlamp adjusters 80a, 80b with two different length towers 82a, 82b for receiving an end 84a, 84b of an adjuster output shaft 86a, 86b when the adjuster output shaft 86a, 86b retracts.